Speciation

• Organism


  Any living thing plant, animal, fungi, eukaryotic cell, bacteria, virus, etc.
• Individual


  A single example of a member of a species. Has a unique genome.
• Population


  Any group of individuals from the same species living in the same location and time. Populations contain a range of alleles from each genome. Populations may be isolated (separated) by distance or physical structure (mountains, rivers) or they may have limited amounts of gene flow between populations.
• Populations with high levels of genetic diversity


  Will generally stay the same and may not evolve quickly
• Populations with low levels of genetic diversity


  Will generally not stay the same and may evolve more rapidly
• Species


  All individuals that have the same physical characteristics, behavioural characteristics, biochemical characteristics, genome, must be able to breed freely with each other (without human intervention), and must be able to produce fertile offspring (F1 generation) who can also produce fertile offspring (F2 generation).
• Community


  All of the populations from different species found in a particular location and time. Each community is unique and depends on the scale used to define the area that the community is found in.
• The more species found in a community the healthier it is considered to be. This is called species diversity.
• Habitat


  The physical conditions that exist in a location that sets limits on the size of individual populations. It defines the conditions that allow individuals to survive or be successful.
• Ecosystem


  All of the habitats in a location that sets limits on the size of the community. These are very hard to define because of the multiple species interactions.
• Biosphere


  All of the ecosystems found on the planet.
• Species


  a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The production of fertile offspring is generally considered to be a requirement.
• Ring species 


  A connected circular series of neighbouring species, which interbreed until the two resultant species do not represent each other.
• Hybrid species 


  Any mix of different but closely related organisms may increase genetic variation/diversity
• "Instant speciation" in this context implies that polyploidy can cause an immediate development of a new species, as the polyploid organism is genetically different from its parents and can no longer interbreed with them.
• Sibling species


  Two (or more) species that are each other's closest relative
• A species flock is a group of closely related species that live in the same habitat.
• Superspecies: a group of largely allopatric species which are descended from a common evolutionary ancestor and are closely related but too distinct to be regarded as subspecies of one species
• Polyploidy is a condition in which the cells of an organism have more than one pair of homologous chromosomes
• Nondisjunction


  a pair of homologous chromosomes has failed to separate or segregate at anaphase so that both chromosomes of the pair pass to the same daughter cell.
• Adaptive radiation


  pattern of evolution; a large number of species form to occupy different ecological niches
• Allopatric speciation


  geographical isolation
• Allele frequency


  Relative proportion of alleles in a population
• Behavioural isolation


  Animals won't reproduce due to differences in courtship, etc
• Biogeography


  A localised population
• Co-evolution


  a pattern of evolution where one species or group changes its genetic composition in response to a genetic change in another
• Comparative anatomy


  Evidence for evolution; homologous structures(related species), analogous structures(unrelated species)
• Pattern of evolution


  Different species living in a similar environment come to look similar
• Deme


  A localised population
• Directional selection


  When one extreme is selected for
• Disruptive selection


  Where both extremes are selected for, against the middle range. This ultimately creates two new species
• Divergent evolution


  When one species branches to form two or more species
• Ecological isolation


  Organisms don't interbreed because of niche differences
• Fossil evidence


  Evidence for evolution; geological layers show species increasingly different to modern species the deeper you go
• Gene flow


  Caused by reproduction between populations
• Gene pool


  All the genes in a reproducing population
• Genetic drift


  Random changes in allele frequencies because of small population size.
• Geographical isolation


  Organisms can't reproduce due to physical separation
• Gradualism


  Patter of evolution; slow changes between populations occur as a result of slightly different selection pressures
• Homologous structure


  Structures with common ancestry, now used for differing functions